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研究生:林建宏
研究生(外文):Jian-Hong Lin
論文名稱:添加PVP改善白金/氫氧磷酸銅/碳黑雙功效觸媒應用於燃料電池之研究
論文名稱(外文):Improving effects of poly (vinyl pyrrolidone) addition on Pt/copper phosphate hydroxide/carbon black bifunctional catalysts for fuel cells
指導教授:顏秀崗顏秀崗引用關係
口試委員:薛康琳蔡毓楨
口試日期:2017-06-26
學位類別:碩士
校院名稱:國立中興大學
系所名稱:材料科學與工程學系所
學門:工程學門
學類:材料工程學類
論文種類:學術論文
論文出版年:2017
畢業學年度:105
語文別:英文
論文頁數:55
中文關鍵詞:氫氧磷酸銅白金觸媒電阻碳黑直接甲醇燃料電池
外文關鍵詞:Copper phosphate hydroxidePt catalystElectric resistanceCarbon blackDirect methanol fuel cells (DMFCs)
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直接甲醇燃料電池應用於小型可攜帶的裝置上,而觸媒以白金為主,因為白金具有優越的催化活性和化學穩定性,但白金觸媒在直接甲醇燃料電池中有兩個問題必須克服:(1)解決一氧化碳對於白金毒化的現象;(2)提升電化學活性,以減少白金的使用量,降低產品成本。根據本實驗室先前的研究成果,氫氧磷酸銅(libethenite),Cu2PO4(OH)在本文中簡稱CuPH,係一種對於醇類氧化有優越功效的磷酸鹽類,且帶有OH基也能增加一氧化碳的解毒功效觸媒成功的改善一氧化碳的毒化現象,但白金還原後分散效果不佳,因此本研究企圖添加PVP改善白金/氫氧磷酸銅/碳黑複合觸媒,更進一步去提升它的分散性以及解毒效應與電化學表現。
本實驗首先將PVP與碳黑混合改善其分散性,再把碳黑置於雙氧水中使其表面富含OH-官能基,之後將氫氧磷酸銅沉積於改質的碳黑上增加其導電性,再把白金還原於其上形成Pt/CuPH-PVP-C觸媒,最後再將此觸媒做熱處理100℃ 3小時。再與未添加PVP之觸媒相互比較,並利用X光繞射(XRD)、場發射掃描式電子顯微鏡(FE-SEM)、場發射穿透式電子顯微鏡即時富利葉轉換(FE-TEM Live-FFT)、X-ray光電子能譜(XPS)、感應耦合電漿質譜儀(ICP-MS)、富利葉轉換紅外線光譜儀(FTIR)與循環伏安法(CV)進行材料分析。
  在電阻方面,Pt/CuPH-PVP-C 3個觸媒明顯低於Pt/CuPH/CB觸媒,FTIR部分也顯示氫氧磷酸銅成功地批覆在改質的碳黑上,透過FE-TEM和FE-SEM可觀察到Pt/CuPH-PVP-C分散性有提升,透過TEM也可以觀察到白金顆粒大小為2.62~3.52奈米。在CV測試中,相較於未添加PVP者氫氣吸/脫附反應電化學活性表面積在添加適量之觸媒表現,由752 提升至895(cm2/mg),在額外添加了兩倍量的碳黑於觸媒,電化學活性表面積更由1067提高至1290(cm2/mg);在甲醇氧化反應中,添加PVP之觸媒最高的質量活性由262提升至328(A/gPt)和最低的起始電位由0.315降至0.256(V)且沒有明顯反應峰出現,顯示無一氧化碳毒化現象,由於這些觸媒中的Cu2+能產生Cu-OH,能進一步把Pt上的CO氧化成CO2故達到解毒效果;在1000圈循環壽命測試下,觸媒之殘留電化學活性表面積仍達80.1%,然而添加過多的PVP會使氫氧磷酸銅較難沉積於碳黑上使白金分散又變差終而降低觸媒效果。此外,在額外加入碳黑後可使阻抗下降進而增加觸媒的催化活性。
在MEA測試下,與Pt/CuPH/CB, Pt/C比較,Pt/CuPH-PVP-C表現出較高的功率密度且有較高之開路電位,除了因具有較低之阻抗外,這些觸媒裡的Cu2+在低電位活化水而產生Cu-OHads,因而創造機會使在Pt上的CO反應成CO2和H+,這些論點也適用於解釋MOR的種種現象,顯然,在DMEC裡的觸媒表現,電阻與CO中毒現象扮演了主要的角色,由添加PVP改善調製的Pt/CuPH-PVP-C確實提高了導電率和解毒功效,而已呈現可接受之性能。
Direct methanol fuel cells (DMFCs) are widely used in small-scale portable applications, and Pt is the superior and major catalyst in them, due to its excellent catalytic activity and chemical stability. However, Pt catalysts have two major problems should be overcome in DMFCs. One is that CO poisoning effects on the Pt catalysts should be deleted, and the other is that the amount of Pt should be reduced by increasing its activity, in order to reduce the cost of devices. Based on the previous study in our laboratory the copper phosphate hydroxide (Cu2PO4(OH)), named libethenite and assigned to CuPH, with the excellent performance in oxidation of olefins and alcohols, reveals hydroxyl radicals which could be used as a catalyst to alleviate CO poisoning effects.
Phosphate salts have shown poor electronic conductivity. In order to enhance its conductivity, the precipitation of CuPH was directly deposited on the surface modified carbon black (CB) to form CuPH/CB. Then, nano-sized Pt was reduced on CuPH/CB to form Pt/CuPH/CB catalyst and finally annealed at 100℃ for 3 hours. However, the agglomeration of catalyst was seriously found. Therefore, in this study, we try to add poly(vinyl pyrrolidone)(PVP) for dispersing catalysts and hence enhancing the detoxifying function as well as electrochemical performance. The features of these catalysts were characterized by the electric resistance measurement, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy – live fast Fourier transform (FETEM-Live FFT), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-mass spectrometry (ICP-MS), Fourier transform infrared (FTIR) spectroscopy and cyclic voltammetry (CV).
It is found that the resistance is reduced from 95.2 to 79 Ω, the ECSA is enhanced from 752 to 805.0 cm2/mg, the mass activity is improved from 262.12 to328 (A/gPt), and the on-set potential is lowered from 0.315 to 0.256V (vs. Ag/AgCl), in the methanol oxidation reaction. Besides, no forward or reverse current peaks are observed, indicating no CO poison effects. For 1000 cyclic life tests, the retained capacity of Pt/CuPH-PVP-C is reaching up to 80.1%.
In membrane electrode assembly (MEA) tests, all prepared Pt/CPH-PVP-C catalysts reveal the greater power density and open circuit voltage than Pt/CuPH/CB and Pt/C (Alfa), since Cu2+ in these catalysts activates the water at low potential to yield Cu-OHads and detoxify the nearby nano-sized Pt poisoned by CO to create the opportunity for forming CO2 and H+, beside the enhanced conductivity. This argument also reasons results of MOR tests out. Obviously, both electric resistance and CO poisoning effect play the major role on the performance of catalysts in DMFC, and the Pt/CuPH-PVP-C improved from Pt/CuPH/CB has revealed the acceptable performance due to its well-dispersed catalysts with enhanced conductivity and detoxifying function.
摘要 i
Abstract iii
Table captions vii
Figure captions viii
Chapter 1 Introduction 1
Chapter 2 Materials and methods 6
2.1 Materials 6
2.2 Preparation of CuPH-PVP-C and Pt/CuPH-PVP-C 7
2.2.1 CuPH-PVP-C 7
2.2.2 Pt/CuPH-PVP-C 7
2.3 Materials characterization 9
2.3.1 Electric resistance measurement 9
2.3.2 FTIR 10
2.3.3 The crystallinity, morphology and microstructure 10
2.3.4 ICP-MS 10
2.3.5 XPS 10
2.4 Electrode preparation and characterization 12
2.4.1 Electrode preparation 12
2.4.2 Electrochemical measurement 12
2.5 Preparation of membrane electrode assembly (MEA) for DMFC single cell polarization test 14
Chapter 3. Results and discussion 15
3.1 Characterization of the CuPH-PVP-C supports and Pt/ CuPH-PVP-C catalysts 15
3.1.1 Resistance measurement 15
3.1.2 FTIR (fourier transform infrared) analysis 16
3.1.3 XRD (X-ray diffraction) 18
3.1.4 FE-SEM (field-emission scanning electron microscope) 21
3.1.5 FE-TEM(field-emission transmission electron microscope) 25
3.1.6 ICP-MS (inductively-coupled plasma mass spectrometry) 31
3.1.7 Chemical states of platinum and copper 33
3.2 Electrochemical characterization 37
3.2.1 HOR (hydrogen oxidation reaction) 37
3.2.2 MOR (methanol oxidation reaction) 42
3.2.3 CO-stripping and Chronoamperometry 46
3.2.4 Membrane electrode assembly (MEA) 47
Chapter 4 Summary and conclusions 50
References 52
[1]William Robert Grove. (1842). LXXII. “On a gaseous voltaic battery.” Philosophical Magazine, pp. 417-420.
[2]M. S. Masdar, S. K. Kamarudin. (2016). “Applications of graphene nano-sheets as anode diffusion layers in passive direct methanol fuel cells (DMFC)” international journal of hydrogen energy, pp. 1-10.
[3]M.B. Ji, Z.D. Wei. (2009).” A novel anode for preventing liquid sealing effect in DMFC.” International Journal of Hydrogen Energy, pp. 2765-2770.
[4]J.Larminie. (2000).” Fuel Cells, in Kirk-Othmer Encyclopedia of Chemical Technology.” John Wiley & Sons.
[5]Ranjan K. Mallick, Shashikant B. Thombre, Naveen K. Shrivastava. (2016).“Vapor feed direct methanol fuel cells (DMFCs): A review.” RenewableandSustainableEnergyReviews, pp. 51-74.
[6]Q. Ye, T. S. Zhao, H. Yang, J. Prabhuram. (2005). “Electrochemical Reactions in a DMFC under Open-Circuit Conditions.” Electrochemical and Solid-State Letters, pp. 52-54.
[7]Anders Oedegaard, Christian Hentschel. (2006). “ Characterisation of a portable DMFC stack and a methanol-feeding concept. ” Journal of Power Sources, pp. 177-187.
[8]R Dillon, S. Srinivasan. (2004). “International activities in DMFC R&D: status of technologies and potential applications.” Journal of Power Sources, pp. 112-126.
[9]M. S. Löffler, H. Natter. (2003). “Preparation and characterisation of Pt–Ru model electrodes for the direct methanol fuel cell.” Electrochimica Acta,, pp. 3047-3051.
[10]E. H. Jung, U. H. Jung. (2007).” Methanol crossover through PtRu/Nafion composite membrane for a direct.” International Journal of Hydrogen Energy, pp. 903-907.
[11]B. R. Padhy, R. G. Reddy. (2006). “Performance of DMFC with SS 316 bipolar/end plates.” Journal of power sources, pp. 125-129.
[12]Yuhao Lu, R. G. Reddy. (2007). “The electrochemical behavior of cobalt phthalocyanine /platinum as methonal-resistant oxygen reduction electrocatalysts for DMFC.” Electrochimica Acta, pp. 2562–2569.
[13]P. Waszczuk, A. Wieckowski. (2001).” Adsorption of CO poison on fuel cell nanoparticle electrodes from methanol solutions: a radioactive labeling study.” Journal of Electroanalytical Chemistry, pp. 55-64.
[14]Wenjun Kang, Rui Li. (2015).” CTAB-reduced synthesis of urchin-like Pt–Cu alloy nanostructures and catalysis study towards the methanol oxidation reaction.” RSC Advances, pp. 94210–94215.
[15]J. Tayal, B. Rawat. (2011). “Bi-metallic and tri-metallic Pt–Sn/C, Pt–Ir/C, Pt–Ir–Sn/C catalysts for electro-oxidation of ethanol in direct ethanol fuel cell.” International Journal of Hydrogen Energy, pp. 14884-14897.
[16]Elson A. de Souza, Raimundo R. Passos. (2016).” Ethanol electro-oxidation on partially alloyed Pt-Sn-Rh/C catalysts.” Electrochimica Acta, pp. 483-489.
[17]M. Rahsepar, Mahmoud Pakshir. (2012).” Synthesis and electrocatalytic performance of high loading active PtRu multiwalled carbon nanotube catalyst for methanol oxidation.” Electrochimica Acta, pp. 246-251.
[18]M. Watanabe, S. Motoo. (1975).” Electrocatalysis by ad-atoms: Part II. Enhancement of the oxidation of methanol on platinum by ruthenium ad-atoms.” Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, pp. 267-273.
[19]L. P. R Profeti, F.C. Simões, P. Olivi. (2006). “Application of Pt + RuO2 catalysts prepared by thermal decomposition of polymeric precursors to DMFC.” Journal of Power Sources, pp. 1195–1201.
[20]R. S. Amin, K. M. El-Khatib, Hammam El-Abd. (2012). “Effect of preparation conditions on the performance of nano Pt‒CuO/C electrocatalysts for methanol electro-oxidation.” International Journal of Hydrogen Energy, pp. 18870–18881.
[21]P. Justin, G. Ranga Rao. (2009).” Enhanced activity of methanol electrooxidation oxidation on Pt‒V2O5/C catalysts.” Catalysis Today, pp. 138–143.
[22]R. S. Amin, K.M. El-Khatib. (2012). “Pt–NiO/C anode electrocatalysts for direct methanol fuel cells.” Electrochimica Acta, pp. 499–508.
[23]T. Iwasita. (2002). “Electrocatalysis of methanol oxidation.”Electrochimica Acta, pp. 3663–3674.
[24]Yu Chuan Lin, Show Kang Yen. (2016). “Preparation and characterization of Pt/copper phosphate hydroxide/carbon black bifunctional catalysts for fuel cells.”
Chung Hsing University Materials science and engineering, pp. 1 -50.
[25]Siyuan Yang, Kejia Xu. (2016). “Solution growth of peony-like copper hydroxyl-phosphate (Cu2(OH)PO4) flowers on Cu foil and their photocatalytic activity under visible light.” Materials and Design, pp. 30-36.
[26]ANDREAS CORDSEN. (1978). “A gbvstal-structure refinement of libethenite.” Canadian Mineralogist, pp. 153-157.
[27]Xiangju Meng, Kaifeng Lin, Xiaoyu Yang, Zhenhua Sun. (2003). “Catalytic oxidation of olefins and alcohols by molecular oxygen under air pressure over Cu2(OH)PO4 and Cu4O(PO4)2 catalysts.” Journal of Catalysis, pp. 460–464.
[28]Feng-Shou Xiao, Jianmin Sun , Xiangju Meng. (2001). “Synthesis and Structure of Copper Hydroxy phosphate and Its High Catalytic Activity in Hydroxylation of Phenol by H2O2.” Journal of Catalysis, pp. 273–281.
[29]Xia Yuan. (2013). “Effect of Poly(vinyl pyrrolidone) on Dispersing Carbon Black Particles.” Advanced Materials Research, pp. 432–436.
[30]Masao Sumita, Kazuya Sakata, Shigeo Asai, Keizo Miyasaka, Hideaki Nakagawa. (1991). “Dispersion of fillers and the electrical conductivity of polymer blends filled with carbon black” Polymer Bulletin, pp. 265-271.
[31]Min Chen, Yangchuan Xing. (2005). “Polymer-Mediated Synthesis of Highly Dispersed Pt Nanoparticles on Carbon Black. ” journal of American Chemical Society, pp 9334–9338.
[32]Hansan Liu, Chaojie Song, Lei Zhang, Jiujun Zhang, (2006) “A review of anode catalysis in the direct methanol fuel cell ” Journal of Power Sources, pp 95–110.
[33]Yu Lin Hsin, Kuo Chu Hwang, Chuin-Tih Yeh. (2007). “Poly(vinylpyrrolidone)-Modified Graphite Carbon Nanofibers as Promising Supports for PtRu Catalysts in Direct Methanol Fuel Cells. ” journal of American Chemical Society, pp 9999–10010.
[34]廖怡萱(2005), "質子交換膜燃料電池陰極觸媒合成, 鑑定及活性測試," 元智大學化學工程與材料科學學系學位論文, pp. 1-157.
[35]Durga Madhab Mahapatra, T. V. Ramachandra. (2013). “Algal biofuel: bountiful lipid from Chlorococcum sp. proliferating in municipal wastewater.” CURRENT SCIENCE.
[36]Shuihua Tang, Leping Sui. (2015). “High supercapacitive performance of Ni(OH)2/XC-72 composite prepared by microwave-assisted method.” RSC Adv, pp. 43164–43171.
[37]Jing Fu, Wenjia Liu, Zhichao Hao, Xiangnan Wu. (2014). “ Characterization of a Low Shrinkage Dental Composite Containing Bismethylene Spiroorthocarbonate Expanding Monomer.” Int. J. Mol. Sci, pp. 2400-2412.
[38]C. Moreno-Castilla, M.V López-Ramón, F Carrasco-Marı́n. (2000). “Changes in surface chemistry of activated carbons by wet oxidation.” Carbon, pp. 1995–2001.
[39]L. Krishna Bharat, Jae Su Yu. (2015). “Ba3(PO4)2 hierarchical structures: synthesis,growth mechanism and luminescence properties.” CrystEngComm, pp. 4647–4653.
[40]P. Kanagaraj, A. Nagendran.(2011). “Performances of Poly(vinylidene fluoride-co-hexafluoropropylene) Ultrafiltration Membranes Modified With Poly(vinyl pyrrolidone)” International Journal of Nanomedicine, pp. 3271–3280.
[41]Deng-Guang Yu, Jun-He Yang. (2003).” Solid dispersions in the form of electrospun core-sheath nanofibers.” Electrochemistry Communications, pp. 306–311.
[42]K Kinoshita. (1988).” Carbon: electrochemical and physicochemical properties.” Journal of the American Chemical Society, p. 541.
[43]A. S. Aricò, A. K. Shukla. (2001).” An XPS study on oxidation states of Pt and its alloys with Co and Cr and its relevance to electroreduction of oxygen.” Applied Surface Science, pp. 33-40.
[44] Zhaolin Liu, Leong Ming Gan, Liang Hong. (2005). “Carbon-supported Pt nanoparticles as catalysts for proton exchange membrane fuel cells.” Journal of Power Sources, pp. 73-78.
[45]Małgorzata Swadźba-Kwaśny, Léa Chancelier, Shieling Ng, Haresh G. Manyar. (2012).” Facile in situ synthesis of nanofluids based on ionic liquids and copper oxide clusters and nanoparticles.” Cite this: Dalton Trans, pp. 219–227.
[46]R. T. Figueiredo, H.M.C. Andrade. (1998). “The Role of the Coprecipitation Sequence of Salt Precursors on the Genesis of Cu-ZnO-Al2O3 Catalysts. Synthesis, Characterization and Activity for Low Temperature Shift Reaction.” Brazilian Journal of Chemical Engineering.
[47]S. Lee, S. Mukerjee, J. McBreen. (1998). “Effects of Nafion impregnation on performances of PEMFC electrodes.” Electrochimica Acta, pp. 3693-3701.
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